Iraqi Violence Strains U.S. Political and Military Strategy and Imperils Pullout Plans

WASHINGTON, Feb. 23 - The violence in Iraq after the bombing of a Shiite mosque this week has abruptly thrown the Bush administration on the defensive, and there were signs on Thursday that American officials recognized new perils to their plans to withdraw troops this year. The American enterprise in Iraq seemed beleaguered on two fronts, political and military.

Senior administration officials in Washington and Baghdad said the next few days would test American and Iraqi resolve, as the United States military, despite pressure to intervene and facing angry accusations that it stood by while Iraq erupted in revenge killings, holds back to see if Iraqis can quell violence by themselves. An unusual daytime curfew in Baghdad scheduled for Friday Prayer could help, the officials said.

Iraqis and some American officials also said the Bush administration might have to rethink its political strategy in Baghdad.

The American ambassador, Zalmay Khalilzad, has reached out to Sunnis, pushing to include them in the government and pressing Shiite leaders hard to keep politicians with ties to Shiite militias out of sensitive security posts. Sunnis have accused these Shiite leaders of running death squads. But Mr. Khalilzad's stance has infuriated Shiites.

Mr. Khalilzad said Monday that the United States would not "invest the resources of the American people" in Iraqi security forces if they were "run by people who are sectarian." The comment provoked unusually direct criticism from Shiite leaders, some of whom suggested that maligning the Iraqi security leadership led to the attack on the mosque in Samarra on Wednesday.

Because sensitive negotiations are continuing and because officials fear that American comments could further inflame a volatile situation, few officials interviewed here or in Baghdad would be quoted by name.

For the moment, American officials said they doubted that Mr. Khalilzad would change course. They said the Americans were pressing Iraqi leaders not to go forward with political negotiations without Sunni participation.

Since the major Sunni party has suspended its participation in the talks, officials hope waiting a few days may allow tensions to recede.

Iraqi security forces were unable -- or, Sunni leaders suggested, unwilling -- to quell the violence after the bombing. In many cases, the American military was either not present or not able to stop Shiite mobs exacting revenge killings across Iraq.

Military officials said the Pentagon was in effect watching and waiting to see what the next 48 hours would bring before deciding on whether a more visible American presence might be needed -- in effect, sending American forces back into areas that they had turned over to the Iraqis.

A senior official said there was no thought being given now to changing the "trajectory" of pulling American forces back and eventually withdrawing part of them this year.

But other administration officials said expanding the American presence might be necessary to contain the violence, partly because despite strenuous efforts, the Iraqi armed forces are still divided along sectarian lines. In particular, Iraqi Sunnis see Shiite-dominated troops as part of the problem, not the solution.

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"Just in the last 36-hour period, Sunni Arabs who were urging us to withdraw forces from cities like Baghdad are now urging us to stay," a senior American official said. "I don't know if the American military is reconsidering its posture, but I can tell you that the Iraqis are reconsidering."

Top aides at the White House, the Pentagon and the State Department all expressed the hope that the new violence did not portend civil war in Iraq. They found it in evidence that all sides were appealing for restraint, even the firebrand Moktada al-Sadr in Baghdad.

"Rather than see a collapse or a setback, I think in some ways, you can see an affirmation that the approach we've been taking has worked," said Adam Ereli, a State Department spokesman. "You've got political leadership acting together on behalf of the common good, and you've got security forces demonstrating that capability and a responsibility as a national entity that we've been working to develop and that has now been put to the test and, I think, is proving successful."

Despite optimistic official comments, the possibility of violent breakdown loomed large. One official called the bombing "an event that brings us to the precipice -- you can see the chasm below that could mean a descent into civil war and everyone is taking a deep breath."

In Baghdad and among some experts, there were questions about how much Mr. Khalilzad's influence could help broker a political solution given the anger between Shiites and Sunnis, and the Shiite anger at Mr. Khalilzad himself.

A high-ranking Shiite official said some of the Sunnis Mr. Khalilzad wanted to bring into the government were Baathists and former members of Saddam Hussein's government.

"The situation is very, very, very bad," said Reuel Marc Gerecht, a fellow at the American Enterprise Institute who supports the American efforts in Iraq. "The bombing has completely demolished what Zalmay was trying to do to get certain Sunnis into the interior and defense ministries."

A statement by Abdul Aziz al-Hakim charging that Mr. Khalilzad's comments on Monday had helped to provoke the bombing were a particularly ominous sign. But American officials said Mr. Khalilzad was unlikely to give up his demands.

"It's important for the Shia leadership to understand our concerns," an American official said. "We're still in conversations with Hakim, and they are unhappy with the ambassador's remarks."

Mr. Khalilzad has gained great popularity among Iraqis, especially among Sunnis, said Saleh Mutlak, a hard-line Sunni Arab member of the new Parliament. He said even the resistance was pleased with his comments about Shiite abuses.

But Mr. Mutlak added that Sunni leaders felt betrayed that American soldiers did not stop the marauding Shiite militiamen on Wednesday, an approach reminiscent of their inaction in the face of looting after the fall of Baghdad in April 2003.

Steven R. Weisman reported from Washington for this article, and Robert F. Worth from Baghdad. Thom Shanker contributed reporting from Washington.

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A version of this article appears in print on February 24, 2006, on Page A00010 of the National edition with the headline: THE STRUGGLE FOR IRAQ: THE ADMINISTRATION; Iraqi Violence Strains U.S. Political and Military Strategy and Imperils Pullout Plans. Order Reprints|Today's Paper|Subscribe